1. Field of the Invention
The present invention relates to a ferro-electric memory device having a ferro-electric capacitor and a method of manufacturing a ferro-electric memory device.
2. Description of the Related Art
In recent years, much attention has been paid to which is the ferro-electric random access memory (FeRAM), a nonvolatile memory using a ferro-electric capacitor.
A conventional FeRAM is formed using, for example, the following process. First, a transistor is formed on a semiconductor substrate. Then, an interlayer insulating film is deposited on the transistor. The interlayer insulating film is then flattened. Then, a lower electrode, a ferro-electric film, and an upper electrode constituting a ferro-electric capacitor are sequentially deposited on the interlayer insulating film. Subsequently, the lower electrode, the ferro-electric film, and the upper electrode are processed by dry etching to form a ferro-electric capacitor.
Such a conventional FeRAM has the following problems. As described above, a dry etching technique is used to process the ferro-electric capacitor. However, the dry etching may damage the ferro-electric capacitor. Moreover, the dry etching may result in the formation of a fence which may in turn induce capacitor leakage. As the ferro-electric capacitor becomes finer-grained in association with an increase in its degree of integration, the capacitor damage and capacitor leakage become severer and are not negligible.